DE3590533T1 - Sorbent and process for the removal of nitrogen oxides, sulfur oxides and hydrogen sulphide from gas streams - Google Patents

Description

Patent attorneys "* T. 8000 MONKS 60

D.8000 MONKS 60 ^; Ϊ I Luclle Gratm punishments 22, ... ,, ·, J D J U O O J

1 June 2, 1986

NOXSO CORPORATION
POBox 586

Library, Pennsylvania 15129 24 421
USA

SORBENS AND METHODS FOR THE REMOVAL OF NITROGEN OXIDES, SULFUR OXIDES AND HYDROGEN SULFUR FROM GAS STREAMS

DESCRIPTION OF THE INVENTION Background of the invention

> The present invention relates to sorbents and to f * '

Process for removing contaminants from gas streams using such sorbents. Are expressed more precisely the sorbents of the present invention versus physical Persistent degradation resulting from repeated adsorption and regeneration. In particular, the Invention on the removal of nitrogen oxides, sulfur oxides and hydrogen sulfide from gas streams.

ι .. The nitrogen oxides occurring as impurities are nitrogen monoxide (NO) and nitrogen dioxide (NO "or N ₃ O ₄ ). The relatively inert nitrogen monoxide is compared to N0 "

often difficult to remove. The lower oxide of nitrogen, N ~ O (nitrous oxide) is used in the amounts that are found in the ambient air or that are usually emitted by exhaust air sources, not as contamination viewed. However, nitrous oxide is broken down (decomposed) into nitric oxide in the atmosphere, and becomes so ultimately a contaminating ingredient.

Sulfur oxides, which are considered to be contaminants Sulfur dioxide and sulfur trioxide.

Particularly undesirable sources of nitrogen and sulfur oxides are power plant exhaust gases, automobile exhaust gases, exhaust gases from heating systems and exhaust gases produced by various industrial processes such as gases from smelting plants and from nitric and sulfuric acid plants.

Emissions from power plants are particularly huge Source of nitrogen oxides and sulfur oxides because of the very large volume of these impurities in such Exhaust gases released into the atmosphere annually. In addition, it is because of the low concentration of impurities in such emissions, typically 0.05% or less nitrogen oxides and 0.3% or less sulfur dioxide, difficult to remove because large volumes of gas must be treated.

Hydrogen sulfide is an impurity in exhaust gases of the following processes: coal gasification, coal liquefaction, oil shale processing, tar sand processing, petroleum processing and use of geothermal energy.

All of the few applicable systems that have heretofore been proposed for the removal of nitrogen oxides from power plant exhaust gases have certain disadvantages. One such method involves spraying the gas with a slurry of

Magnesium hydroxide or carbonate; the slurry will regenerated by treatment with ammonia. This process produces ammonium nitrate as a by-product, which is difficult to remove and also requires cooling and reheating of the exhaust gas stream.

Methods for removing nitrogen oxides from gases using various sorbents are discussed in the following references: US Patent 2,684,283 to Ogg, Jr. et al. (Sorbent: mass of iron (III) oxide and sodium oxide), US Patent 3,382,033 by Kitagawa (sorbent: porous carrier, impregnated with FeSO. + H ₃ SO ₄ , FeSO., FeSO. Χ. (NH ₄ ) “SO ., PdSO ₄ , KMnO ₄ , KMnO ₄ + H ₃ SO ₄ , KClO ₃ , NaClO NaOH, NaClO ₃ + NaOH, Na ₃ MoO ₄ , K ₂ S ₃ O ₃ , Na ₃ S ₂ O ₃ + NaOH, Na H PO ₄ , Na ₃ O ₃ , As ₃ O ₃ + NaOH, CuCl ₃ or ICI ₃ + NaOH); U.S. Patent 3,498,743 to Kyllonen (using a bed of finely divided solid sodium carbonate) and U.S. Patent 3,864,450 to Takeyama et al. (Use of a catalyst consisting essentially of carbon impregnated with sodium or potassium hydroxide).

Various methods have been proposed for the removal of sulfur dioxide from power plant exhaust gases, but they do all have drawbacks. For example, wet spray systems based on aqueous alkaline substances such as e.g. Solutions of sodium carbonate or sodium sulfite or slurries magnesium oxide, lime or limestone normally requires the exhaust gas to be cooled to around 55 C, so that a water phase is formed. At these temperatures, the treated gas has to be heated again so that it is sufficient Heat is developed in order to achieve a sufficient rise in the plume. They also deliver such Process Products that raise the problem of solid waste disposal.

Different solid phase processes for the removal of Sulfur dioxide, which has heretofore been proposed, also has disadvantages. The use of e.g. limestone or Dolomite for the adsorption of sulfur dioxide causes waste disposal problems as the solid does not is regenerated.

Process for the removal of sulfur oxides from gases using various sorbents are discussed in the following references: US Patent 2,992,884 to Bienstock et al. (Sorbent: alkali metal oxide dispersed on a carrier such as aluminum oxide or chromium oxide), US patent 3,411,865 to Pijpers et al. (Sorbent: alkali metal oxide and iron oxide, dispersed on a carrier such as aluminum oxide, Magnesium oxide or chromium oxide), U.S. Patents 3,492,083 and 3,669,617 to Lowicki et al. (Sorbent: oxide, hydrated Oxide or hydroxide of aluminum, zinc, iron or manganese and an oxide or hydroxide of an alkali metal or alkaline earth metal), U.S. Patent 3,589,863 to Frevel (porous alkali metal hydrogen carbonate aggregates), U.S. Patent 3,755,535 to Naber (Sorbent: activated alumina or magnesia impregnated on an inert carrier), US Patent 3,948,809 to Norman et al. (Sorbent: bauxite and alkali metal carbonate), U.S. Patent 3,959,952 to Naber et al. (Sorbent: aluminum oxide carrier, impregnated with copper and aluminum, magnesium, titanium or zirconium) and GB 1.154.009 (sorbent: vanadium compound and an alkali metal compound).

U.S. Patent 3,880,618 to McCrea et al. refers to the simultaneous removal of sulfur and nitrogen oxides from gases using alkalized alumina or alkali metal carbonate or oxide.

U.S. Patent 4,071,436 to Blanton, Jr. et al. describes the removal of sulfur oxides using reactive alumina.

Alkalized aluminum oxide is dealt with in the following publications: D. Bienstock, J.H. Fields and J.G. Myers, "Process Development in Removing Sulfur Dioxide from Hot Flue Gases", 1st Bench-Scale Experimentation Report of Investigations 5735, United States Department of the Interior, pp. 8-17, U.S. Patent 3,551,093 to J.G. Myers et al. and U.S. Patent 3,557,025 to Emerson et al. As will be explained in more detail below, alkalized aluminum oxide sorbents showed previously used for the treatment of flue gases, as a result of the chemical processes of Adsorption and regeneration strong aging of their resistance to wear and tear.

The alkalized alumina sorbent is .. and ₃ CO ₃ prepared by precipitation from dawsonite (NaAl (OH) "CO.) Of a solution of Al ₇ (SO ₄₎ Na at 90 ⁰ C. The resulting solid is then heated to 130 C to dry the remaining moisture and crushed to a smaller particle size. Since the dawsonite is formed by precipitation, it has a very dense, solid structure with only little space for the absorption of SO «. The chemically bound HO and CO must therefore be removed by calcining at high temperatures in order to form a porous sorbent.

NaAl (OH) ₂ CO _{3 (s)} heat _> NaAlO _{2 (g)} f H ₂ Cy CO _{3 (g)}

The calcined sorbent (NaAlO ₂ ), known as alkalized aluminum oxide, can then be used in a process for treating flue gas.

Sodium is an integral part of the entire crystal structure of alkalized aluminum oxide. The concentration of sodium in alkalized alumina is about 25 Wt%.

The chemical process of adsorption causes changes in the sorbent and creates internal forces that cause that Sorbents of a type similar to those of the present invention, e.g., alkalized alumina, wear out (crumble) quickly. The sorbents of the present invention are subject to this wear problem associated with sorbents of a similar type such as alkalized alumina connected, not.

As the adsorption proceeds, the layer of suIfit / sulphate product grows in both directions the initial pore boundary from taking place, the growth into the substrate material, however, is for the impregnated Sorbent limited to a very thin layer. When the layer of the product in the alkalized alumina material it grows into it, splits and deforms the crystal structure. The volumes of the ■ product molecules

and Na "SO.) are much larger than those of the unimplemented Molecules (Na ~ O) and therefore creates the product layer very disturbed and weakened material. As the growth proceeds, the product layer bends and splits paths for the product deeper and deeper into the substrate body. The effect of this process is the emergence of a physical one Tensions that dramatically increase the wear and tear of the sorbent. The growth proceeds both in the impregnated as also in the simultaneously precipitated sorbent until all the sodium or all free spaces are used up are occupied within the pores. Most of the surface, and consequently the sodium, is in the many very small pores of the impregnated sorbent. The dimension of these pores continuously shrinks up to one Order of magnitude that is smaller than the average pore diameter. In reality, many of these pores have the Size of the product molecule.

US Patents 4,323,544 and 4,426,365, both assigned to the assignee of the present invention, relate to methods of removing nitrogen oxides using a sorbent, the alumina having a surface area of about 20 m ² / g and an alkaline one Contains constituent which comprises at least one salt of group IA (alkali metal) or group HA (alkaline earth metal).

As stated above, it is a major disadvantage of the previously used sorbents for the removal of sulfur oxides and / or nitrogen oxides that such sorbents suffer from signs of wear. The sorbents of US patents 4,323,544 and 4,426,365 involved in the removal of contaminants from exhaust gas streams are very effective, begin to undergo irreversible decomposition at 175 C. Accordingly it would be very beneficial to have a sorbent available that is not only capable of removing gaseous Impurities like sulfur oxides and nitrogen oxides is effective but also isn't able to withstand high temperatures withstand without being subject to wear and tear.

The present invention provides sorbents which do not degrade excessively as a result of chemical use will not wear out excessively.

The present invention further provides a method for Removal of nitrogen oxides and possibly sulfur oxides from exhaust gas streams at the same time in a single time Procedure available. In addition, it is possible according to the invention to treat exhaust gas streams at temperatures at which the flows still contain enough heat to cause the plume to rise sharply from the chimney. The sorbents of this invention remove NO ~ as well as that relatively inert NO in an effective manner.

The present invention also enables nitrogen oxides and sulfur oxides to be removed from exhaust gases (this Process provides elemental nitrogen and elemental sulfur), without the formation of solid waste products that a Would create waste problem. The process of the present invention consumes only relatively small amounts of natural gas or other hydrocarbon fuels.

The present invention also enables the removal of hydrogen sulfide.

The present invention relates to a sorbent for removing gaseous nitrogen oxides, sulfur oxides and Hydrogen sulfide from exhaust gas streams that contain one or more of the gaseous nitrogen oxides, sulfur oxides and / or hydrogen sulfide contain. The sorbent according to the invention comprises an aluminum oxide substrate, preferably a gamma-aluminum oxide substrate, and an alkali or alkaline earth compound, i.e., an alkali metal (a Group IA metal) or an alkaline earth metal (a Group IIA metal). The alkali or alkaline earth metal is in an amount between 50 and 40Ol ^ per

2 2

m substrate and preferably between 100 and 350 wg per m Substrate and more preferably between 150 and 250 µg per m substrate included.

The method of the invention comprises contacting an exhaust gas stream containing oxides of nitrogen and optionally oxides of sulfur, with a sorbent which Alumina and an alkali or alkaline earth component contains in order to sorb at least parts of the nitrogen oxides and the sulfur oxides. The sorbent in which the alkali or Alkaline earth component is incorporated, contains this in

2 an amount between 50 and 400 μg per m substrate and

2 preferably between 100 and 350 * Ag per m and especially

preferably between about 150 and 250 a.g per m. The nitrogen and sulfur-laden sorbent is then made by heating

the sorbent in a reducing atmosphere, e.g. in one containing hydrogen or hydrogen sulfide Gas stream, regenerated up to about 650 C, with the nitrogen being removed as elemental nitrogen and the Sulfur is removed as elemental sulfur. Alternatively, the regeneration is carried out by heating the sorbent in a inert atmosphere carried out at temperatures up to about 350 C to 650 ° C, with the nitric oxide as nitric oxide is removed and then the hot sorbent is brought into contact with a reducing agent, the sulfur being used as elemental sulfur is removed. Some of the sulfur produced during regeneration can be used to Produce hydrogen sulfide while recovering the rest of the sulfur. The regenerated sorbent will then used for further removal of oxides of sulfur and nitrogen.

The present invention comprises a method for removing hydrogen sulfide from a gas stream. This method for hydrogen sulfide removal includes contacting of the gas stream containing hydrogen sulfide with the sorbent described above at temperatures in the range from 300 C to 650 C. The regeneration of the used sorbent for such a process is carried out using Steam carried out, with the hydrogen sulfide from the sorbent is displaced and removed from the sorbent surface. The excess steam is then condensed, resulting in a Stream of high concentration of hydrogen sulfide for the provides direct use in further process steps.

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Brief description of the drawings

Fig. 1 is a summary of wear test results, a sorbent that has been available for a long time is compared with sorbents according to the invention.

2
Figure 2 is a graph of surface area (m / g) versus Na ^ CO ^ content (wt%) demonstrating the effect of sodium loading on the surface of gamma-alumina substrate.

Fig. 3 is a flow sheet illustrating a process according to the invention for the simultaneous removal of sulfur oxides and nitrogen oxides from flue gas.

Fig. 4 is a flow sheet illustrating a process according to the invention for the removal of nitrogen oxides from flue gas.

Figure 5 is a flow sheet illustrating a process for removing hydrogen sulfide from an H ₂ S laden gas stream in accordance with the present invention.

6 shows the results of a mercury porosity test for determining the distribution of the pore volume in gamma alumina substrate.

Fig. 7 is a schematic diagram showing macro and micro pores of a sorbent, the present one Invention corresponds.

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Exact description of the invention

In the present invention, alumina means a form of alumina with increased surface area, usually more than 100 square meters per gram and often as high as 400 or 500 square meters per gram. For NOx removal alone, surfaces of 200 m / g are effective. Many methods are known in the art using where such forms of alumina can be made. For example, alumina can have a large surface area from a sodium aluminate solution or such a sol by adding an acidic substance such as carbon dioxide or Mineral acid or an acidic salt such as aluminum sulfate can be precipitated. Other methods of making High surface area aluminum oxides include the dehydrogenation of aluminum hydroxides such as aluminum hydrate (Al (OH) -) or bauxite. Activated bauxite is because of it a particularly useful starting material for alumina in the present invention. Another A useful source of high surface area alumina for the purposes of the present invention is the by-products the hydrolysis of aluminum alcoholates such as aluminum triisopropoxide. Such aluminas that are characterized by extremely high purity, expressed by the absence of other metallic elements, can recently can be purchased at relatively low prices.

Gamma alumina is the preferred form of alumina for the substrate of the sorbent according to the invention.

The alumina substrate of the present invention contains pores that receive the alkali or alkaline earth component. In one embodiment of the present invention, the Substrate by adhesion of individual particles of gamma-aluminum oxide made together. Such particles contain pores. Accordingly, such a substrate has internal

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- γ- - - -3690533

Particle pores with a certain small diameter d, and pores between the individual particles, i.e. Interstices, with a certain small diameter d ". The pores d i have an average pore diameter between 30 and 400 angstroms, preferably between 60 and 200 angstroms and in particular between 80 and 100 angstroms. The pores d_ have an average Particle diameter of 80 to 3000 Angstroms, preferably between 100 and 1000 Angstroms and in particular between 200 and 500 angstroms.

The total pore volume of the aluminum oxide substrate according to the invention comprises a range between 0.4 and 0.8 cm / g, preferably between 0.6 and 0.8 cm / g. The surface of the Alumina substrate ranges between 100

2 2

m / g and 500 m / g.

The exclusive scope of the present invention also lies within the scope of the present invention Use of gamma aluminum oxide (without any other ingredient such as sodium) as a sorbent. Such gamma aluminas have a pore volume between 0.4 and 0.8

3 2 2

cm / g and a surface area between 100 m / g and 500 m / g. Such sorbents can be used in the methods described herein can be used in the same way, i.e. at the same temperatures and residence times, as sorbents that contain a Contain alkali metal or an alkaline earth metal.

The alkali or alkaline earth component of the invention Sorbent is an alkali metal, i.e. a metal of group IA, namely Li, Na, K, Rb, Cs or Fr, or an alkaline earth metal, i.e. a metal of the group HA, namely Be, Mg, Ca, Sr, Ba or Ra. The preferred ingredients are sodium, potassium and calcium, with sodium being particularly preferred.

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The alkali or alkaline earth component of the invention Sorbent can advantageously be used as a hydroxide, carbonate, Nitrate, acetate, or as another soluble salt of a Group IA or Group HA metal.

It should be understood that mixed salts are used can, i.e. salts (1) with one and the same metal but different anion components or (2) with one and the same anion but different metal components or (3) with different metal and anion components can be used. For example, a mixture of sodium acetate and carbonate or a mixture of Potassium and sodium carbonate or a mixture of potassium acotate and sodium carbonate are advantageously used will.

The sorbent according to the invention can 'according to the technique of "dry impregnation" can be produced. The alkali or alkaline earth component, e.g. sodium, is applied to the substrate, e.g. gamma-alumina, by spraying the substrate with a salt solution of the alkali or alkaline earth component, e.g. a sodium carbonate solution. The impregnated substrate is then heated to the remaining To dry off moisture. During the production of the sorbent according to the method described above, it was found that that the alkali or alkaline earth component is evenly distributed within the pores of the substrate. the chemical reactions that occur during the sorbent production described above expire are the following:

^Na 2 ^CO 3 (s) ^{+ Al} 2 ° 3 (s) ^{+ H} 2 ° (l)> ^Na 2 ^CO 3 (s) ^{+ A1} 2 ° 3- ^H 2 ^O (s)

+ NaAl (OH)

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- γι. ■ ..-: / 3690 533

The dry one; impregnated sorbent is the end product and can be used immediately for exhaust gas cleaning processes. In contrast, it requires alkalized aluminum oxide sorbent, such as that developed by the US Bureau of Mines was subjected to high temperature calcination before it could be used in such processes.

In further contrast to alkalized aluminum oxide, in which the sodium is distributed throughout the entire solid matrix the sorbent according to the invention only on the inner surface, i.e. on the porous structures of the substrate coated with the alkali or alkaline earth component.

The sorbent according to the invention can furthermore be characterized in that the layer of the alkali or alkaline earth component, for example Na ₃ CO-, on the surface of the porous structure does not exceed the diameter of approximately one molecule.

Without wishing to be bound by a particular theory about the effect, it is assumed that it is a critical one Amount of the alkali or alkaline earth component on the substrate surface e.g. the sodium loading per pore volume or surface of the substrate below which the physical strength of the sorbent particles is significantly weakened, leading to wear and tear.

Fig. 1 is a graph with a series of beams, which shows the percent weight loss, plotted against the number of cycles, for the three subjected to the wear test ι sorbents. Each bar represents the amount of percentage weight loss in the attrition test over a period of 10 minutes.

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The sorbents tested had the following physical properties:

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Physical properties sorbent A ^ sorbent B "sorbent C.

% Sodium 3.50 3.46 6.55

Density, am. Pounds / feet ³ 50.0 4 2.4 46.3

2
Surface, m / g

Pore volume with water, cm ³ / g 0.22 0.78 0.62

The sorbents B 'and C' correspond to the present invention, the sorbent A 'corresponds to the state of the art Sorbent.

The sorbents were in an "Accelerated Air Jet Attrition" (AJAA) test device over a period of 30 minutes examined away. The AAJA device was manufactured by W.R. Grace and Co. developed. AAJA tests measure the amount of wear and tear of sorbents that are subjected to different operating conditions over a number of chemical cycles

A typical AAJA test device is described below:

A 50 g sample of sorbent, previously sieved to +10 to -20 mesh, is placed in an inverted 1-1 Erlenmeyer wide neck flask (45 mm diameter) made of Pyrex. In the middle of its bottom the piston has a hole with a 6.2 cm in diameter covered with a 40 mesh screen. The neck of the flask is closed with a nylon stopper, which has a concave bottom approx. 1.1 cm deep. One 1/4 "outside diameter (1/8" inside diameter) tube The stainless steel is inserted through a hole in the plug to a point that is level with the concave At the bottom, and the tube opening is closed with a small one

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• Jie · ■■: ■■■■ ;. . ".. - ^

Covered piece of 60 mesh sieve. The stopper is fastened with the help of two rubber O-rings that sit in grooves that are in the stopper sides are notched, held on the neck of the flask.

Air is obtained from a pressurized gas cylinder that is connected to a Pressure regulator is equipped. The air flows through flexible 3/8 "

"TEFLON" hoses to a drying tube, valve, rotometer (0-6.43 ACFM at 21 ° C, 1 atm) and into the 1/4 "tube that fits into the stopper on the neck of the upturned Erlenmeyer flask. The Erlenmeyer is held in place by a ring clamp attached to a stand and placed in a laboratory fume cupboard. the Before starting the test, the piston is set to the correct height on the stand.

The sorbent B ″ was investigated at four different adsorption temperatures in the range from 107 ^° C. to 290 ^° C. Each time the sample was subjected to five cycles of adsorption / regeneration. The first adsorption was carried out in a fluidized bed. The sample was then used for further investigation A single sample of the sorbent B 'was also tested over 15 operating cycles at a constant adsorption temperature of 120 C. From Fig. 1 it can be seen that the rate of wear of this sorbent depends on the adsorption temperature or the number of chemical cycles The percent weight loss in the second and third ten minutes of the wear test for each sample in this series was essentially the same, in most cases less than 1% of the sample weight.

It is assumed that the noticeable different weight losses during the first 10 minutes in the wear tests on the sorbent B 'are due to various methods in the sample

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production are due. All samples in this series were in contrast to the 5-Cyclen test at 290 ⁰ C at the start by 20 minutes coarse Rättern of 250 grams of the sorbent in a mechanical shaker and then filtering out of a sample of 150 grams of the fraction with 10 χ 20 mesh size manufactured. For the test at 290 C, small amounts of the sorbent were carefully hand-sifted to remove any particles smaller than 10 × 20 mesh prior to testing. As can be seen from Figure 1, the weight loss in the first ten minutes of the test on this sample was significantly less than any other in this series. It is believed that a substantial portion of the weight loss in the first ten minutes for all other samples in this series is due to the presence of particles smaller than 20 mesh in the initial sample placed in the fixed bed reactor.

1 also shows the results of wear tests carried out on sorbent A 'and sorbent B " . The wear rate of sorbent A' was significantly higher than that of sorbent B 'in the tests on both fresh and cycled material. The sample of Sorbent A 'tested after five cycles at 177 ° C showed a weight loss of 41.5% after the first ten minutes of the wear test, compared to a corresponding loss of 1 to 2% for all samples of Sorbent B' tested The main difference between these two sorbents is the pore volume; both have approximately the same surface area and sodium loading. The pore volume of sorbent B 'is more than three times that of sorbent A'.

Sorbent C has twice the sodium loading and about 65% of the surface area of sorbent B '. Sorbent C was also tested after five cycles at 290 ⁰ C.

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A)

The sorbents according to the invention (sorbents B " and C ') showed very little percentage weight loss even at temperatures up to 290 ° C. and at 15 cycles (one absorption - one regeneration per cycle). In contrast, the sorbent with a pore volume of 0.22 cm / g (sorbent A ') is subjected to a dramatic increase in the rate of wear at 177 C. It is assumed that the lower pore volume limits the space available for the expansion of the product layer, which leads to a marked increase in the stresses in the sorbent particle The test run with Sorbent A 'at 177 C was discontinued after the first ten minutes because of excessive initial weight loss.

The effect of sodium loading on the surface of gamma-alumina is shown in FIG. When the sodium load is low, the layer of the sodium salt, ie of Na-CO ,, is approximately the strength of a molecule. When the load increases so much that most of the inner surface is covered, the molecules of Na ₇ CO ₃ begin to pile up. As a result, the thickness of the Na ^ CO - ^ - layer will increase proportionally to the loading. FIG. 2 shows that the surface remains roughly the same if the Na "CO -.- loading remains below about 8%, since it is only partially covered with a monomolecular layer of Na ₃ CO ₃ . However, if the Na ₂ CO ₃ loading rises to over 8% (for example 12 to 20%), the diameter of the Na ₂ CO 3 layer increases rapidly. The expansion of the Na ^ CO ^ layer leads to reduced pore diameters and consequently to reduced surfaces.

A comparison of the typical properties of an inventive The following table provides sorbent and alkalized aluminum oxide:

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Alkalized according to the invention

Sorbent aluminum

Total sodium loading,% 3.5 20-25

Surface area, ^m2 / g 222 47

Pore volume, cm / g 0.69 0.69
Average pore diameter, nm 12.4 58.7

The exact chemical or crystallographic form of the sorbent is not critical to the present invention in the narrower range. It is assumed that the aluminum oxide in the sorbent produced has insufficient crystallinity and is present as gamma-Al ^ O and gamma A1 "O_H" O. If the sodium is used in the form of Na "CO", it is present in the sorbent as Na ₃ CO ₃ , Na ₂ CO ₃ H ₂ O, gamma-NaA10 ₂ , beta-NaA10 ₂ and NaAl (OH) ₂ CO ₃ . The sorbent can change its structure after regeneration compared to that in the fresh state. The alkaline component can be present as oxide, hydroxide, carbonate or aluminate or as a mixture of these compounds when the sorbent is freshly made or after it has been regenerated. Different amounts of sulfur- or nitrogen-containing salts can also be present, such as, for example, nitrates, nitrite, sulfate, sulfite or sulfide.

Various other metal oxides such as those of copper, iron, vanadium, zinc, molybdenum or those of the rare elements Earths can also be used in amounts up to about 10 atomic percent, based on the total number of atoms of Aluminum, alkaline component and other metal (s) are present.

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■ • 2a- ·

Of the nitrogen oxides and sulfur oxides-containing exhaust gas stream is contacted at temperatures of from 85 ° C to about 200 ⁰ C and preferably from 90 ⁰ C to 150 ⁰ C with the sorbent in contact. At higher temperatures, the effectiveness of the nitrogen oxide removal is reduced, while at lower temperatures the exhaust gas flow would have to be reheated or compressed in order to allow the exhaust gas plume to be drawn off accordingly.

The sorbent and the exhaust gas can be in a fixed bed, in a fluidized bed or in a moving bed according to the state of the art Technique appropriate procedures are brought into contact. If the contact is in a fixed bed, that includes Residence time of the gas ranges from 0.1 to about 10 seconds, but is a larger range for fluid bed operation possible.

If the sorbent with nitrogen and. is optionally sulfur-laden, preferably to a level greater than about one equivalent of nitrogen plus sulfur for every five equivalents of the alkaline component, it is regenerated. For this purpose, one equivalent of sulfur is regarded as half a gram atom, one equivalent of nitrogen as one gram atom, one equivalent of alkali metal as one gram atom and one equivalent of alkaline earth metal as half of a gram atom. The sorbent is regenerated in contact with a regenerating gas stream containing at least 0.01 atmospheric partial pressure of a reducing gas such as hydrogen or hydrogen sulfide at temperatures from about 350 ° C. to about 700 ° C. over a period of time sufficient to maintain a substantial part of the sorbent capacity for the sorption of nitric oxide and sulfur oxide to clear again. The minimum time required for the regeneration depends to a large extent on the temperature and the partial pressure of the hydrogen sulfide in the regeneration gas and can range from a few minutes at 750 ^° C. to 12 hours or more at lower temperatures

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Temperatures fluctuate.

The regeneration gas preferably contains carbon dioxide or water vapor, and more preferably contains both Carbon dioxide as well as water vapor. Alternatively, the sorbent after contact with the hydrogen sulfide-containing Regeneration gas treated with carbon dioxide and / or water vapor. If carbon dioxide and / or water vapor is used come, these are preferably used in amounts totaling at least about one mole of carbon dioxide and / or Correspond to water vapor per mole of the oxide gas sorbed prior to regeneration.

A convenient method of obtaining a suitable regeneration gas, which contains carbon dioxide is that of the catalytic gas phase reaction of water vapor, sulfur and a hydrocarbon such as methane, which is essentially takes place according to the following reaction equation:

CH ₄ -l · 2H ₂ O + 4S ^ " ^4H 2 ^{S + C0} 2 *

For the purpose of this invention the expression "use of hydrogen sulfide in the regeneration gas" should be used other compounds which substantially form hydrogen sulfide under the regeneration conditions include, viz that of carbon disulfide or carbon oxysulfide in the presence of water vapor, such as those caused by the following reactions:

CR., + ?H O 2H ^ S. 2
COS 2 -ς;
O 2 - * - co " 2
^ = - CO ^ ~ 2

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During regeneration, sulfur forms in the regeneration stream, and this is condensed in the stream below the sorbent. During this procedure, at least one Part of the hydrogen sulfide is converted into elemental sulfur. Any unreacted hydrogen sulfide can be added the condensation of sulfur can easily be reused.

After the sorbent has been regenerated, it is brought to the sorption temperature cooled, e.g. by contact with a cooler stream of water gas. The sorbent is then used again for used for the removal of sulfur oxides and nitrogen oxides.

In one embodiment of the present invention, a concentrated stream of nitrogen oxides produced by a sorbent such as the sorbent described here from exhaust gas streams that containing such oxides, was removed after the regeneration of the sorbent, i.e. after expelling the nitrogen oxides from the Sorbent, can be returned to the source of these nitrogen oxides, e.g. to a steam boiler. In this embodiment the nitrogen oxide level in the boiler reaches a certain equilibrium, e.g. 600 ppm, and so the recovered Nitrogen oxides decompose in the steam boiler without increasing the parts nitrogen oxide per million in the escaping exhaust gases.

If reference is made to FIG. 3, in which the same numerals mean the same structural elements, a flue gas flow is here 12 from a power plant (not shown) containing both SO and NO, which by a fluidized bed absorber 14 containing sorbent according to the invention is passed. The adsorber 14 has a fluidizing grid 15. The sulfur oxides and nitrogen oxides are adsorbed on the surface of the sorbent and removed from the flue gas flow.

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The saturated sorbent 16 is then fed to a staged fluidized bed heater 18, wherein the sorbent temperature with the aid of hot air 20 provided by the air heater 22 into which a flow of Outside air 24 and a fuel stream 26, e.g. natural gas, open out, is increased to over 532 C (1000 F). At the same time, the sorbed NO is removed from the sorbent and in the hot gas stream entrained, which passed through the cyclone 28 and via the path 30 with the combustion air flow of the power plant (not shown) is mixed.

The hot sorbent is brought via the path 34 from the sorbent heater 18 into a moving bed regenerator 32. In the traveling bed regenerator 32 the sorbent is brought into contact with a regeneration gas stream 36. The regeneration gas 36 reacts with the sorbed sulfur oxides and delivers in the process elemental sulfur. The waste gas stream 38, which contains elemental sulfur, is passed into a sulfur separator and a Defogging system 45 transported, wherein a water vapor stream 42, a water stream 44 and a stream of elementary Sulfur 46 are formed. A branch 40 from the sulfur separator and the defog system 45 is to Regenerator 3 2 returned.

The regenerated sorbent is passed via path 48 after check valve 50 to a staged fluidized bed sorbent cooler 52 where it is contacted with atmospheric air supplied via path 54 to bring its temperature to about 120 ° C (250 ° F) reduce. The hot, atmospheric air 56 is then passed to the gas heater 22 where its temperature is raised to well above 532 ° C (1000 ⁰ F) so that they can be used as heating medium in the fluidized bed heater 18th

- 25 -

The cooled sorbent is on the way 58 with the help of air (way 54) through a pneumatic elevator (way 60) with the Stream 64 transported into the cyclone separator 62. The cyclone separator 62 separates the stream 64 into air 66 and sorbent 68. The sorbent stream 68 enters the absorber 14. The waste gas from the absorber 14 flows out via the path 70.

In Fig. 4, a flue gas stream that contains NO from an incinerator (not shown), which
sulfur-free fuel is used, passed through a fluidized bed sorbent device 74 containing sorbent and having a fluidizing grid 76. The NO-free sorbent is routed back to the sorption device 74 for reuse on the path 108 and the entrained air is separated via the cyclone 104 and exits via the path 110. The NO is removed by sorption on the surface of the sorbent. The NO -free exhaust gas (clean gas flow) is then released into the atmosphere via path 78.

When the sorbent is saturated with NO, it is transported on route 80 to a staged fluidized bed heater, in which it is brought into contact with a stream of hot air 84. The hot air 84 is supplied by an air heater 86 produced into the fuel 88, e.g. natural gas, and ambient air 90 flow. The hot air removes the sorbed

NO from the surface of the sorbent. The NO -containing gas stream χ χ ^r

exits heater 82 on path 92 and is directed to cyclone 94. The air 96 from the cyclone 94 is in the Incinerator (not shown) used. The NO-free sorbent stream 98 from the fluidized bed heater 82 is according to the invention then via a pneumatic lift 100 with the aid of air that is supplied on the path 102, transported on path 106 into cyclone 104.

- 26 -

In Fig. 5, a gas stream 112, the hydrogen sulfide, e.g. from an oil shale retort or a coal gasification plant, contains as an impurity, passed through a fluidized bed sorption device 114, the sorbent accordingly of the present invention. The sorbent is located on the grid 116 in the sorption device 114. Hydrogen sulfide is removed from the gas stream by sorption on the surface of the sorbent. The purified gas stream, the exiting sorbent device 114 on path 118 is used for its intended purpose. One with hydrogen sulfide saturated sorbent stream 120 from sorption device 114 is transported into a fluidized bed regenerator 122, where it is brought into contact with a stream of water vapor 124. The sorbent is located in the regenerator 122 the grate 126. The stream 128 of water vapor and hydrogen sulfide from the regenerator 122 is then passed into a water separator 130, in which the remaining steam is removed being a highly concentrated hydrogen sulfide gas stream 132 and a water stream 134 are formed. The free sorbent from regenerator 122 is via path 136 returned to sorbent 114 for reuse.

Fig. 6 shows the results of a mercury porosity test to determine the distribution of the pore volumes in the gamma-aluminum oxide substrate of the present invention. "D" in Fig. 6 refers to the diameter. The distribution has two Maxima and can be separated into a group of micropores with a probable diameter in the range of 10 to 100 angstroms and a group of macropores with radii that are at least one and possibly two orders of magnitude are larger than the radii of the micropores.

Figure 7 is a schematic diagram showing macro and micro pores in the substrate of the sorbent of the present invention. The three-dimensional circular areas consist of

- 27 -

closely packed uniform, spherical grains. The macro pores correspond to the holes in the spaces between the grains, while the micro pores correspond to the pores within the individual grains. Most of the surface area of the sorbent is in the micropores, but the greater part of the pore volume is in the macropores. It is assumed that the micropores with their large surface area are where most of the chemical reaction takes place. The size of the micropores, 10 to 100 Angstroms, is similar to the size of the molecules that are formed during adsorption /. When SO _{2 is} adsorbed, the products expand in the free spaces available in the pores. A mechanical load can be exerted on the compact structure under conditions of high SO2 loading and / or low micropore volume. The stress results in an unacceptable rate of wear on the sorbent.

The invention will now be explained with reference to the following, non-limiting examples:

* from SO ₀

² - 28 -

'- Example 1

Gamma-alumina, manufactured by the Davison Division of WR Grace & Co. according to U.S. Patents 4,154,812 and 4,279,779, has been surface coated with Na ₂ CO ₃ equivalent to 8% by weight Na ₀ CO ₃ , treated. To do this, the required amount of Na ₀ CO _{3 was} dissolved and the solution was applied by an initial high humidity method. The solid was then heated to drive off the moisture, leaving a layer of Na ₃ CO ₃ . The physical properties of the resulting sorbent were as follows:

Weight percent sodium 3 5

2
N_ surface., M / g 222

Pore volume by H ₀ O, cm / g η το

3
Density, cm / g η ar

Example 2

A sample of 100 g of sorbent, prepared according to Example 1 (only gamma-aluminum oxide) was placed in a fixed bed reactor with a diameter of 61 cm × 5 cm, which was heated by means of a temperature-controlled tubular furnace. The sorbent was brought into contact at 120 ° C. with a real flue gas from a coal-fired boiler, which had the following approximate volume composition: 74% N ₃ , 12% CO ₂ , 9% H ₃ O, 4% O ₃ , 0.23% SO ₂ , 0.05% NO and 0.0025% ^Ν0 ₂ · ^The flow rate of the flue gas was 10 liters per minute, measured at 25 ° C and 1 atmosphere pressure.

Samples from the reactor exhaust gas were checked for nitrogen oxides (NO and NO ₀ , expressed as NO) and for sulfur dioxide with the following

L * X

examined the results:

* (2 feet X 2 inches) - 29 -

Flow time (minutes)

% NOx removal *

15 30 45 60 75 90

100 98 95 90 80 58

Flow time % SO ^ distance * (Minutes) 100 6th 100 12th 100 18th 95 24 82 30th 40 45

. _. "_ _ .J. -inn / τ (NO exhaust gas concentration)

* Percent NO removal = 100 (1 - χ ^

(NO inlet concentration)

same goes for the percentage of SO _? -Distance

Example 3

A sample of 100 g of sorbent, produced according to Example 1 (with 8% by weight Na ^ CO.,), was actually with one brought into contact with the flue gas occurring, whereby the same operating conditions and the same composition of the

- 30 -

led gas stream as used in Example 2. The results were as follows:

Flow time (minutes)

% NOx removal *

15 30 45 € 0 75 90 105

100 97 94 94 93 88 65

Flow time (minutes)

SO ₂ -Distance *

30th

60

90

120

150

100
94
83
57
42

If one compares the results from Example 2 (only gamma-aluminum oxide) with the results from Example 3 (gamma-aluminum oxide plus 8% Na-CO ₃ ), it becomes clear that the sorbent from Example 3 improves the removal results with increasing flow time from NE and SO delivers.

Λ. X

Example 4

A sample of

(8% by weight

with .a gas,

100 g of sorbent, produced according to Example 1

Na ₂ CO ₃

containing) was heated to 570 C and

which contained 30% by volume H "S and 70% by volume N",

- 31 -

brought in contact. The flow rate of the gas was 60 liters per hour, measured at 25 C and 1 atmosphere pressure. Samples from the reactor off-gas were taken continuously examined for H_S with the following results:

Flow time

(Minutes)% H S distance *

2.5 100

5 100

7.5 100

10 90

12.5 60

15 40

* Percentage HS distance = 100 (1 - (^ S exhaust gas concentration)

/ If

H-S 'exhaust gas concentrate.)

Example 5

The used sorbent from Example 3 was heated to 550 ° C. in N. gas and then introduced for 50 minutes of a gas stream containing 30% H “S in N ~ with 60 liters per Hour regenerated. Then the sorbent was brought into contact with steam and cooled to 120.degree. After a second Sorption cycle as in Example 3, the results were as follows:

- 32 -

Flow time
(Minutes)

NO distance

15 30 45 60 75 90 105

100 98 96 95 94 88 63

Flow time
(Minutes)

60

90

120

SO distance

100
S 6
70
35

Similar results were obtained after exposing this sample to the adsorption / regeneration cycle a total of 15 times had been.

Example 6

Two sorbent samples according to the invention were five cycles of Subjected to adsorption / regeneration and then examined in an "Air Jet Attrition Apparatus" (AJAA) to determine whether the chemical cycles changed the wear properties. The physical properties of the two sorbents were as follows before being subjected to chemical cycling;

- 33 -

5 A. 222 3 59 O, 3 68 0533 Sorbent O, Sorbent B. 4.4 ,8th , 5 78

SORBENS

Sodium content, wt .-%

N_ surface, m ² / g 2 \

3
Pore volume (with H ₉ O), cm / g 0.22

3
Density, g / cm (

One type of sorbent of the present invention is composed of a layer (or layers) of Na ₉ CO ₃ deposited on the surface of a gamma-alumina substrate. The sorbents used in Example 6 were made from different substrates, but the method of applying Na ₉ CO ₃ to the surface of the substrate was the same in each case. Electron micrographs showed that the surface of sorbent B, using a gamma-alumina substrate supplied by the Davison Division of WR Grace & Co., consists of similarly shaped platelet-like structures with large areas of normal bonding. Investigations of the surface of the sorbent A, for which a substrate made of Reynold's gamma-aluminum oxide was used, could be shown by means of electron microscopy as consisting of tiny, irregularly shaped particles with small areas of normal bonding.

The sorbents A and B were placed in a fixed bed reactor with a diameter of 61 cm 5 cm / which was heated by means of a temperature-controlled tubular furnace. The sorbents A and B were brought into contact at 177 ° C. with a flue gas from a coal-fired boiler, which occurs in reality and which has an average of 74% nitrogen, 12% CO, 9% H ₂ O, 4% O ₂ , 0 , 21% SO ₂ , 0.05% NO and 0.0025% NO ₃ . The flow rate of the flue gas in both cases was 10.0 liters per minute, measured at 25 ° C. and 1 atmosphere pressure. The sorbents A and B were subsequently

(2 feet χ 2 inches) - 34 _

by heating the

'35

Fixed bed reactor

in

to 500 ° C and

subsequent introduction of a gas flow from 30

HS and 70%

N "with 60 liters per hour, measured at 25 ° C and 1 Atmosphere pressure, regenerated. After the regeneration, the sorbents A and B were brought into contact with water vapor, cooled to 120 C and then reused in the absorption process.

After five cycles of adsorption, a sample of 50 g each of sorbent A and sorbent B was taken and placed in an "Air Jet Attrition Apparatus "(AJAA) examined for wear strength. The results of this examination were as follows:

A. Cyclic Adsorption Test duration AJAA number temperature (Minutes) Weight B. fresh (° C) 30th loss Sorbent 5 cycles 10 f Q, \
V Ό / Sorbent fresh 177 30th 24.3 5 cycles - 30th 41.5 Sorbent 177 4.3 3.0

Those measured in this test for fresh (unreacted) sorbent A. Wear losses were more than five times that for fresh sorbent B. Additionally deteriorated The performance of sorbent A was significantly influenced by the chemical cycles, while that of sorbent B did not decline. The loading of the sorbent was similar for sorbents A and B and corresponded to 5 grams of adsorbed SO "per 100 grams of sorbent. It the relatively poor performance of sorbent A compared to sorbent B is believed to be due to differences in surface structure of the two substrates.

- 35 -

Example 7

The sorbent B used in Example 6 was then examined whether the rate of wear is due to an increase in the adsorption temperature or an increase in the number of adsorption and regeneration cycles would be affected. The processes of adsorption and regeneration were the same as those described in Examples 3 and 5. The average loading of the sorbent fluctuated with the adsorption temperature and ranged from 5 to 2.5 grams of adsorbed SC- per 100 grams of sorbent at 88 ° C and 300 ° C, respectively. The sorbent load A series of tests with 5, 10 and 15 cycles at 120 ° C. resulted in a constant 5 grams of adsorbed SO2 per 100 grams Sorbent. The results were as follows:

Adsorption Test duration AJAA temperature (Minutes) Weight Cyclic (° C) 30th loss number 3 0 (%) Fresh 105 30th 4.3 5 cycles 120 30th 3.9 5 cycles 177 30th 3.2 5 cycles 285 30th 3.0 5 cycles 120 30th 1.7 10 cycles 120 3.8 15 cycles 5.2

The results presented above show that the rate of wear of the sorbent B by increasing adsorption temperature or increasing number of chemical cycles is not changed.

- 36 -

- ft D -

Example 8

The AJAA test is commonly used in the industry for determination the relative wear rates of various solid catalysts are used. In order to be able to predict wear losses in operations on an industrial scale, must however, the test data correlates with actual wear losses measured in pilot or large-scale plants will. Samples of fresh (unreacted) Sorbent B were presented to the United States Department of Energy ("DOE") for testing with its AJAA device. The following results were obtained:

Entire ver Entire ver lust (% by weight) lust (% by weight) Test time (AJAA as in Ex. (AJAA of the DOE) (Minutes) 6 used) 0.12 10 2.6 0.27 20th 3.8 0.49 30th 4.2

Obviously the AJAA device submits to the example 6 passed the sample to a tougher wear test. Such differences are found in tests with the AJAA device in which the results by the shape of the test device, i.e. by the shape of the air inlets (small differences in the shape of the Air intakes may cause differences in test results) very easily affected, not uncommon. Nevertheless, all of Examples 6, 7 and 9 (below) obtained by identical procedures using the same test device. the Data can therefore be compared to determine the relative wear characteristics of the samples examined.

37 -

The US Department of Energy reported that for samples Batches that had an equilibrium wear rate of 0.02-0.03% of the circulating solids inventory, Losses obtained in the AJAA test were that. are similar to those mentioned above for fresh sorbent B, these Measurements on a fluidized bed adsorber were carried out on a pilot scale.

Example 9

A sample of sorbent B was treated with Na “CO_, (equivalent to 21 % By weight) coated. The physical properties of this sorbent, designated as Sorbent C, are as follows specified. The physical properties of this substrate and those of sorbent B are shown for comparison. It should be noted that the sorbent C is significantly less Surface and pore volume occupied as the substrate or • sorbent B.

Substrate
gamma alumina

% Sodium

2
N ₂ surface area, m / g

Pore volume (due to H ₉ O),

3
cm / g

Density, g / cm

216 0.78

0.62

Sorbent B. Sorbent C. 3. 5 9, 222 122 0. 78 0. .1 .48

0.68

0.86

Sorbent C was subjected to five adsorption cycles in exhaust gas at 260 ° C by a procedure identical to that of Example 3. The sorbent C was regenerated by heating the reactor to 650 ^° C. in nitrogen and then passing in a stream of 30% H_ and 70% N_ for 40 minutes at a rate of about 1 liter per minute. The results of this test are given below here.

- 38 -

An identical set of tests using H "S as Reduction gas is shown for comparison. It should be noted that treatment with H "S" is the sorbent not fully regenerated. In addition, since the SO_ loading increases with H ~ during regeneration, the loss increases due to wear and tear.

Regeneration agent Number of cycles Average SO_ loading * Test time (min) AJAA weight loss (%)

* Average SO ₂ load = adsorbed SO ₃ (g)

^H 2
5 H ₂ S
5 13th 6th 20th 30th 19.4 5.0

100 g of sorbent

It is believed that the unacceptably high rate of wear exhibited by sorbent C is caused by a combination of lower surface area and high SO2 loading. When the double surface area sorbent B shown above and 40% SO ₂ loading was subjected to a similar test (see Example 8), the measured wear loss was 2 to 5% by weight in a 30 minute test. The size of the surface area of the sorbent, the pore volume and the SO2 loading are decisive factors in achieving economically acceptable rates of wear of the sorbents.

The present invention can be in other specific embodiments exist without deviating from their basic idea or essential properties thereof, and accordingly one should refer to the appended claims rather than to the preceding description, since those the Specify the scope of the invention.

Claims (55)

Ao claims (original version) 1. Sorbent for removing gaseous nitrogen oxides, Sulfur oxides and hydrogen sulfide from waste gas streams, being the sorbent (a) an alumina substrate and (b) an alkali or alkaline earth component comprises, wherein the amount of the alkali or alkaline earth component is between 50 and 400 L * -g per m ^ of the substrate . 2. Sorbent according to claim 1, wherein the amount of the alkali or alkaline earth component between 100 and 350 i> g per m ^ des Substrates is. 3. Sorbent according to claim 1, wherein the amount of the alkali or alkaline earth component between 150 and 2 50 /> g per m ^ des Substrates is. 4. The sorbent of claim 1, wherein the alumina is gamma-alumina is. 5. Sorbent according to claim 1, wherein the alkali or alkaline earth component is selected from the group consisting of sodium, lithium, potassium, rubidium, cesium, magnesium, calcium, Consists of strontium and barium. 6. Sorbent according to claim 1, wherein the alkali or alkaline earth component Sodium is. 7. The sorbent of claim 1, wherein the substrate has internal pores with an average pore diameter between 30 and has 400 angstroms 8. The sorbent of claim 1, wherein the substrate has internal pores with an average pore diameter between 60 and has 200 angstroms. 9. The sorbent of claim 1, wherein the substrate has internal pores with an average pore diameter between 80 and 100 angstroms. 10. The sorbent of claim 1, wherein the substrate has an average Has pore diameter between substrate particles of 80 to 3000 angstroms. 11. The sorbent of claim 1, wherein the substrate has an average Has pore diameter between substrate particles of 100 to 1000 angstroms. 12. The sorbent of claim 1, wherein the substrate has an average Has pore diameter between substrate particles of 100 to 500 angstroms. 13. The sorbent of claim 1, wherein the pore volume of the substrate is between 0.4 and 0.8 cm ^ / g. 14. Sorbent according to claim 1, wherein the surface of the substrate is between 100 m ^ / g and 500 m ^ / g. 15. Process for removing nitrogen oxides and / or Sulfur oxides from a gas containing nitrogen oxides and / or sulfur oxides that contacting of the gas comprising a sorbent, the sorbent (a) an alumina substrate and (b) an alkali or alkaline earth component comprises, wherein the amount of the alkali or alkaline earth component is between 50 and 400 |> g per m ^ of the substrate. • ka. 16. The method of claim 15, wherein the in-contacting, at a temperature between 85 ° C and 200 ^c C is performed. 17. The method of claim 15 wherein the contacting with the sorbent is effected in a fixed bed and wherein the contact time is between 0.1 and 10 seconds. 18. The method of claim 15, wherein the contacting is made with the sorbent in a fluidized bed. 19. The method of claim 15, wherein the amount of alkali or Alkaline earth component between about 100 and 350 M-g per m ^ of the substrate. 20. The method according to claim 15, wherein the amount of the alkali or alkaline earth component is between 150 and 250 j + q per m ^ of the substrate. 21. The method of claim 15 wherein the alumina is gamma alumina. 22. The method of claim 15, wherein the alkali or alkaline earth component is selected from the group consisting of sodium, lithium, potassium, rubidium, cesium, magnesium, Consists of calcium, strontium and barium. 23. The method of claim 15, wherein the alkali or alkaline earth component Sodium is. 24. The method of claim 15, wherein the substrate is internal Has pores with an average pore diameter between 30 and 400 Angstroms. 25. The method of claim 15, wherein the substrate has internal pores with an average pore diameter between 60 and 200 angstroms. . te 26. The method of claim 15, wherein the substrate has internal pores with an average pore diameter between 80 and 100 angstroms. 27. The method of claim 15, wherein the substrate is a has average pore diameter between substrate particles of 80 to 3000 angstroms. 28. The method of claim 15, wherein the substrate has an average pore diameter between substrate particles from 100 to 1000 angstroms. 29. The method of claim 15, wherein the substrate is a has an average pore diameter between substrate particles of 200 to 500 Angstroms. 30. The method of claim 15, wherein the pore volume of the Substrate is between 0.4 and 0.8 cm ^ / g. 31. The method of claim 15, wherein the surface area of the substrate is between 100 m ² / g and 500 m ² / g. 32. Process for removing hydrogen sulfide from a gas containing hydrogen sulfide, the bringing into contact of the gas comprising a sorbent, the sorbent (a) an alumina substrate and
(b) an alkali or alkaline earth component comprises, wherein the amount of the alkali or alkaline earth component is between 50 and 400 jjq per m ^{2 of} the substrate. 33. The method of claim 32, wherein the in-contacting is carried out at a temperature between 85 ⁰ C and 20O ⁰ C. 34. The method of claim 32, wherein the contact time is between 0.1 seconds and 10 seconds. 35. The method of claim 32, wherein the contacting is made with the sorbent in a fluidized bed. 36. The method of claim 32, wherein the amount of alkali or Alkaline earth component between 100 and 350 ug / m ^ des Substrates is. 37. The method of claim 32, wherein the amount of alkali or Alkaline earth component between 150 and 250 JUg / rn ^ des Substrates is. 38. The method of claim 32, wherein the alumina is gamma alumina. 39. The method according to claim 32, wherein the alkali or alkaline earth component is selected from the group consisting of sodium, lithium, potassium, rubidium, cesium, magnesium, Consists of calcium, strontium and barium. 40. The method of claim 32, wherein the alkali or alkaline earth component Sodium is. 41. The method of claim 32, wherein the substrate is internal Pores with an average pore diameter between 30 and 400 Angstroms. 42. The method of claim 32, wherein the substrate is interior Has pores with an average pore diameter between 60 and 200 Angstroms. 43. The method of claim 32, wherein the substrate is internal Has pores with an average pore diameter between 80 and 100 Angstroms. 44. The method of claim 32, wherein the substrate has an average pore diameter between substrate particles from 80 to 3000 angstroms. - Sf - 45. The method of claim 32, wherein the substrate is a has an average pore diameter between substrate particles of 100 to 1000 angstroms. 46. The method of claim 32, wherein the substrate is a has an average pore diameter between substrate particles of 200 to 500 Angstroms. 47. The method of claim 32, wherein the pore volume of the substrate is between 0.6 and 0.8 cm ^ / g. 48. The method of claim 32, wherein the surface area of the substrate is between 100 m ^ / g and 500 m ^ / g. 49. sorbents for removing gaseous nitrogen oxides, Sulfur oxides and hydrogen sulfide from waste gas streams, wherein the sorbent is gamma-alumina having a pore volume comprised between 0.4 and 0.8 cm ^ / g and having a surface area between 100 m ^ / g and 500 m ^ / g. 50. A method for removing nitrogen oxides, sulfur oxides and / or hydrogen sulfide from a gas which contains nitrogen oxides, sulfur oxides and hydrogen sulfide, which comprises bringing the gas into contact with the sorbent according to claim 49 at a temperature between 85 ° C and 200 ⁰ C includes. 51. Process for removing nitrogen oxides from a Exhaust gas stream containing nitrogen oxides, the exhaust gas being generated by a source which facilitates the removal of the Nitrogen oxides from the gas by contacting the gas with a sorbent, regenerating the sorbent expel the oxides of nitrogen therefrom, and recycle it comprising expelled oxides of nitrogen to the source. 52. A method for removing nitrogen oxides according to claim 51, wherein the sorbent is the sorbent of claim 1. 24 241 Claims (amended version) 1. A sorbent resistant to wear and tear, that in a fluidized bed for the removal of gaseous nitrogen oxides, sulfur oxides and hydrogen sulfide Exhaust gas streams can be used, this sorbent (a) a gamma-alumina substrate with a top 2 2 area between 100 m / g and 500 m / g and a pore volume between 0.6 and 0.8 cm, this being gamma-aluminum oxide has a distribution of pore sizes with two maxima, since it contains micropores and macropores, the micropores have an average pore diameter in the range between 80 and 400 angstroms, and (b) an alkali metal component that is based on this Substrate is applied, whereby the amount of alkali 2 metal components in the range between 50 and 400 uQ per m of the substrate lies,
includes. 2. Sorbent according to claim 1, wherein the amount of alkali 2 metal constituents in the range between 100 and 350 µg per m of the substrate. 3. Sorbent according to claim 1, wherein the amount of alkali 2 metal constituents in the range between 150 and 250 µg per m of the substrate. 4. deleted 5. The sorbent of claim 1, wherein the alkali metal component is selected from the group consisting of sodium, Consists of lithium, potassium, rubidium, cesium, and francium. 6. The sorbent of claim 4, wherein said alkali metal component is sodium. 8th deleted 9. The sorbent of claim 1, wherein the substrate has internal pores with an average pore diameter between 80 and 100 angstroms. 10. The sorbent of claim 1, wherein the macropores of the substrate have an average pore diameter of 80 up to 3000 angstroms. 11. The sorbent of claim 1, wherein the macropores of the substrate have an average pore diameter of up to 1000 angstroms. 12. Sorbent according to claim 1, wherein the macropores of the Substrates have an average pore diameter of up to 500 angstroms. 13th deleted 14th deleted 15. Process for removing nitrogen oxides and / or sulfur oxides from a gas containing nitrogen oxides and / or sulfur oxides which contains the contacting of this gas with a sorbent, said sorbent (a) an alumina substrate and (b) comprises an alkali or alkaline earth component, wherein the amount of the alkali or alkaline earth component im The range is between 50 and 400 µg per m of the substrate. 16. The method of claim 15 wherein the contacting at a temperature between 85 C and 200 C. is carried out. 17. The method of claim 15, wherein the contacting with the sorbent is carried out in a fixed bed and wherein the contact time ranges between 0.1 and 10 seconds. - 3 - 18. The method of claim 15, wherein the contacting is made with the sorbent in a fluidized bed 19. The method of claim 15, wherein the amount of Alkali or alkaline earth component in the range between about 2
100 and 350 ug per square meter of substrate. 20. The method of claim 15, wherein the amount of Alkali or alkaline earth component in the range between 150 2
and 250 ixg per m of substrate. 21. The method of claim 15 wherein the alumina is gamma-alumina. 22. The method of claim 15, wherein the alkali or alkaline earth component is selected from the group consisting of It consists of sodium, lithium, potassium, rubidium, cesium, magnesium, calcium, strontium and barium. 23. The method of claim 15, wherein the alkali or alkaline earth component is sodium. 24. The method of claim 15, wherein the substrate has internal pores having an average pore diameter between 30 and 400 angstroms. 25. The method of claim 15, wherein the substrate has internal pores having an average pore diameter between 60 and 200 angstroms. 26. The method of claim 15 wherein the substrate has internal pores with an average pore diameter between 80 and 100 Angstroms. 27. The method of claim 15, wherein the substrate is a has an average pore diameter between the substrate particles of 80 to 3000 Angstroms. 28. The method of claim 15, wherein the substrate is a has an average pore diameter between the substrate particles of 100 to 1000 angstroms. 29. The method of claim 15, wherein the substrate has an average pore diameter between the substrate particles from 200 to 500 angstroms. 30. The method of claim 15 wherein the pore volume of the substrate is between 0.4 and 0.8 cm / g. 31. The method of claim 15, wherein the surface of the 2 2 Substrate is between 100 m / g and 500 m / g. 32. Process for removing hydrogen sulfide from a hydrogen sulfide-containing gas which the contacting comprises this gas with a sorbent, this sorbent (a) an alumina substrate and (b) an alkali or alkaline earth component, the amount of the alkali or alkaline earth component in the The range is between 50 and 400Mg per m of the substrate. 33. The method of claim 32, wherein the bringing into contact at a '
is carried out. Bring at a temperature between 85 C and 200 C. 34. The method of claim 32, wherein the contact time is between 0.1 seconds and 10 seconds. . Βλ- 35. The method of claim 32, wherein the contacting is made with the sorbent in a fluidized bed. 36. The method of claim 32, wherein the amount of the Alkali or alkaline earth component in the range between 100 2
and 350 µq per m of the substrate. 37. The method of claim 32, wherein the amount of the alkali or alkaline earth component is in the range between 150 2
and 250 u, q per m of the substrate 38. The method of claim 32, wherein the alumina is gamma alumina. 39. The method of claim 32, wherein the alkali or alkaline earth component is selected from the group consisting of Consists of sodium, lithium, potassium, rubidium, cesium, magnesium, calcium, strontium and barium. 40. The method of claim 32, wherein the alkali or The alkaline earth component is sodium. 41. The method of claim 32, wherein the substrate has internal pores with an average pore diameter between 30 and 400 angstroms. 42. The method of claim 32, wherein the substrate has internal pores having an average pore diameter between 60 and 200 angstroms. 43. The method of claim 32, wherein the substrate is internal Has pores with an average pore diameter between 80 and 100 Angstroms. 44. The method of claim 32, wherein the substrate is a has an average pore diameter between the substrate particles of 80 to 3000 Angstroms. 45. The method of claim 32, wherein the substrate has an average pore diameter between the substrate particles from 100 to 1000 angstroms. 46. The method of claim 32, wherein the substrate has an average pore diameter between the substrate particles from 200 to 500 angstroms. 47. The method of claim 32, wherein the pore volume of the substrate is between 0.6 and 0.8 cm / g. 48. The method of claim 32, wherein the surface of the 2 2 Substrate is between 100 m / g and 500 m / g. 49. Sorbents for the removal of gaseous nitrogen oxides, sulfur oxides and hydrogen sulfide from exhaust gas streams, this sorbent gamma-alumina with a pore volume between 0.4 and 0.8 cm / g and with a surface area 2 2 contains between 100 m / g and 500 m / g. 50. Process for removing nitrogen oxides, sulfur oxides and / or hydrogen sulfide from a gas that contains nitrogen oxides, Contains sulfur oxides and hydrogen sulfide, which bringing this gas into contact with the sorbent of claim 49 at a temperature between 85 ° C and 200 ° C. 51. Process for removing nitrogen oxides from a Exhaust gas stream containing nitrogen oxides, the exhaust gas originating from a source which the removal of these nitrogen oxides from the gas by bringing the gas into contact with a sorbent, regenerating the sorbent to drive off the nitrogen oxides therefrom, and returning the expelled nitrogen oxides to the source includes. 52. The method for removing nitrogen oxides according to claim 51, wherein said sorbent is the sorbent of claim is. 53. The sorbent of claim 5, wherein the alkali metal component Potassium is. 54. The sorbent of claim 10, wherein the alkali metal component Sodium is. 55. The sorbent of claim 10, wherein, the alkali metal component Potassium is.